Cylinder Head Fun

As you saw in the article we did about the initial engine disassembly, the cylinder head looked a bit raspy after spending the better part of 20 years doing nothing but taking up space on the top of the Sprint’s engine.  The photos below show how cruddy the exhaust port was, not to mention the combustion chamber.  We suspect that an open exhaust valve allowed water and moisture to enter the engine, which contributed to the frozen piston problem.

Below are before andafter photos of the cylinder head which was masterfully reworked by Harley head expert Frank Romero at Crazy Horse Speed Shop in North Bergen, NJ.  We hadn’t set our sights on building a full-on race bike, so Frank recommended a good valve job, port matching on both ends (including the intake manifold), and keeping any polishing to a minimum. Although the exhaust port was severely pitted, Frank felt that for our application it would be detrimental to port the opening to the point where all visible pits were gone. To do it correctly, the intake side would also required complimentary hogging of the port. With all other internals remaining stock, we’d probably end up losing power.  Thus, Frank ported both ports to reasonable dimensions despite the exhaust port pitting.  Frank feels the pits will fill with carbon in short order, which will smooth the surface naturally.

If I look happy with the results, it’s ‘cause I am. Check of the “before” and “after” photos that follow. I laid ‘em out side-by-side so you could see what Crazy Horse got for raw material, and what they returned.

GREAT JOB, Frank!

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